The invention relates to a wood burning heating system for homes and commercial buildings. The system also supplies hot water for domestic and other purposes.
Many different structures for heating systems, boilers, furnaces, and fireplaces are known in the art for using all sorts of suitable fuels including coal, coke, wood, and similar fuels to avoid the use of fuel oil.
Oil is the most convenient fuel as far as combustion control, relatively clean burning, and efficiency are concerned. However, recent oil price rises have caused extensive efforts, including substantial research, for the return to using historically older fuels such as wood and coal, especially for home heating purposes. Gas produced by wood coking results in a fuel, the combustion of which is well controllable. However, the wood gas production is at present too involved for individual production for home heating purposes.
U.S. Pat. No. 4,088,113 (McIntire et al) discloses a wood burning, automatic swimming pool heater. The door of the combustion chamber is removable for using the heater as a fireplace. A set of heat exchanger pipes is located in the combustion chamber and apparently connected to a swimming pool. This type of system is not suitable for home heating because the water temperature in a swimming pool is too low for heating purposes.
U.S. Pat. No. 2,406,673 (Drummond) discloses a coal burning furnace. The coal is charged through a top loading door into a hopper reservoir above the combustion chamber whereby the coal is to slide gradually down by gravity into the combustion chamber. A secondary combustion chamber above the main combustion chamber contributes to a more efficient combustion. The system is pressurized and uses a small water reservoir as an integral part of the furnace.
U.S. Pat. No. 1,710,665 (Mertzanoff) discloses a coal fueled water heater wherein the combustion chamber is substantially surrounded by a first water chamber which communicates by gravity flow with a further water chamber above the combustion chamber. The total water volume is insufficient to constitute a reservoir for heat storage.
U.S. Pat. No. 2,396,252 (Cross) discloses a self-stoking coal fired water heater equipped with a water jacket surrounding the combustion chamber. Again, the water jacket does not provide any heat storing capacity. Similar considerations also apply to U.S. Pat. No. 2,014,658 (Masonick).
The prior art apparently has not recognized the need for a compromise that must be made because a wood or coal fire, once started, cannot be controlled to an extent similar to that of an oil or gas flame. Such fine controls as are available for controlling or regulating an electric heater are also not available for controlling a wood or coal fire. The induced and/or forced draft controls that have been used heretofore for controlling wood or coal fires are insufficient to achieve a relatively convenient heating system. A wood fueled heating system could be considered relatively convenient if it meets the following requirements: reloading of wood into the firebox should be necessary only about once a day, it should be safe against overheating, it should be substantially independent of other fuels such as electricity for control purposes and the dryness and type of wood used should not be too critical. Further, prior art systems aim at simplicity, yet there is room for improvement for achieving simplicity and with it affordability.